Stopper with an obstuctor for a can and method for the production of said stopper

ABSTRACT

The invention relates to a stopper, provided with an obstructor ( 1 ), for a can. Said stopper comprises a cap ( 3 ) provided with a central opening ( 5 ) and an annular skirt ( 7 ), and an annular shaft ( 17 ) extending around the opening, in addition to a capsule ( 19 ) which is detachably fixed, by means of a tear element ( 23 ), to a free edge ( 25 ) of the shaft opposite the opening. The tear element joining the shaft to the capsule is placed in an entrance area at an angle in the free edge of the shaft. At least one sealing lip ( 37 ) is disposed on the inner surface of the shaft, and the cap, skirt and capsule of the stopper are molded in a single piece without any welding or the addition of another component or detachable part. The invention also relates to a method for the production of said stopper by offset injection in a region which is outside the cap.

This application is a 371 of international applicationPCT/CA2003/001026, which claims priority based on Canadian patentapplication No. 2,418,456 filed Feb. 11, 2003, which is incorporatedherein by reference.

FIELD OF THE INVENTION

The present invention relates to an obturation cap especially adaptedfor use to close the neck of water containers, usually of three or fivegallons, that are intended to be used in upside down position in waterdispensing machines, also known as “water dispensers”.

The invention also relates to a method for manufacturing this obturationcap by a single injection of plastic material in a mold especiallydevised for this purpose.

TECHNOLOGICAL BACKGROUND

Obturation caps of the above mentioned types have already beendisclosed. In this connection, reference can be made to U.S. Pat. No.5,222,530 of 1993 and to its European counterpart EP-0,641,713-B1 of1997, both issued in the name of ELKAY MANUFACTURING CO. withdesignation of Henry E. BAKER et al as inventors.

Obturation caps of this type are extremely interesting but are presentlydifficult to manufacture in one single injection, without having toproceed to an ultrasonic welding or another type of welding. In thisconnection, reference can be made to the comments made in the preambleof U.S. Pat. No. 5,392,939 of 1995 in the name of Walter E. HIDDING etal where, in column 2, lines 3 to 20, mention is made to the problem ofmolding the cap disclosed in U.S. Pat. No. 5,121,778 of 1992 to ELKAYMANUFACTURING CO. which derives from the same parent application as U.S.Pat. No. 5,222,530 mentioned hereinabove and where, in the same column,mention is also made to the fact that it is impossible to manufacturesuch a cap by injection in one single piece.

International patent application No. WO 02/060808 A1 published in 2002in the name of W. KRASKA discloses an obturation cap of the same type asmentioned hereinabove, as well as a method for manufacturing this cap byinjection in one single piece. However, the potential problem with themethod proposed in this international patent application is that onecannot necessarily obtain all the requested angulations and aconsistence of the frangible connection. Once cannot also obtainnecessarily all the requested curves to ensure that the sleeve of thecap be provided with one or more internal sealing tongues and the upperedge of this sleeve be inclined or bevelled to facilitate engagement ofthe plug within the sleeve during extraction of the liquid dispenser.However, these structural characteristics are actually essential whenone wants to obtain a cap that is water tight and air tight and thusperfectly hygienic, in addition of having it also with tamper proofproperties.

SUMMARY OF THE INVENTION

Therefore, a first object of the present invention is to provide animproved obturation cap, of the type comprising:

-   -   a lid provided with a central opening;    -   an annular skirt extending in a given direction all around an        external periphery of the lid, said skirt being provided with a        central axis and being devised and sized to be connected to the        neck of the container;    -   an annular sleeve extending all around the central opening of        the lid in the same direction as the skirt and coaxially        therewith, the central opening and the sleeve surrounding the        same being both sized to receive and guide the feed tube of the        liquid dispenser used with the container closed by the cap; and    -   a plug fixed in a detachable manner by means of a frangible        connection to a free edge of the sleeve opposite to the central        opening, said plug being coaxial to the sleeve and devised to be        separated from the same when the container closed by the cap is        inserted into the liquid dispenser, the frangible connection        between the sleeve and the plug being located in an angularly        oriented inlet zone made in the free edge of the sleeve for, on        one hand, facilitating tearing of the frangible connection        during insertion of the cap onto the feed tube of the liquid        dispenser and, on the other hand, facilitating engagement of the        plug within the sleeve during extraction of the feed tube, the        plug then acting as an obturator, said plug being also provided        with internal gripping means for fixing it temporarily to an        upper end of the feed tube during water flow, and with external        sealing means for closing the sleeve when the container is        removed from the liquid dispenser, the plug being then pulled        back to the sleeve and forced into the same by the feed tube        while the same is extracted from the sleeve.

In accordance with the invention, this obturation cap is improved inthat:

-   -   the angularly oriented inlet zone where is located the frangible        connection between the sleeve and the plug comprises a portion        above the frangible connection with an inwardly oriented        inclination angle ranging from 20° to 60° and a portion below        the frangible connection with an inwardly oriented inclination        angle ranging from 5° to 20° ;    -   at least one sealing tongue is located on the inner surface of        the sleeve to improve sealing of the cap and ensure prealignment        of the plug within the sleeve during extraction of the feed        tube.

Another object of the invention is to provide a method for manufacturingthis cap.

Both of these objects and their advantages will be better understoodupon reading the non-restricting description that follows of a preferredembodiment of the invention, made with reference to the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional perspective view of an obturation capaccording to a preferred embodiment of the invention;

FIG. 2 is a cross-sectional enlarged view of part 11 of FIG. 1;

FIG. 3 is a transversal cross-sectional view of the cap shown in FIG. 1;

FIG. 4 is an enlarged cross-sectional view of the left hand-side of thesleeve and the plug of the cap shown in FIG. 3;

FIG. 5 is a schematic cross-sectional view of the neck of a containerprovided with the cap shown in FIG. 1, during installation within awater dispenser just before tearing of the frangible connection;

FIG. 6 is a view similar to FIG. 5, showing the container and its caponce installed within the water dispenser;

FIG. 7 is a view similar to FIGS. 5 and 6, showing the way the plug isforced back by the feed tube within the sleeve of the cap when thecontainer is removed from the water dispenser;

FIGS. 8 to 1 5 are cross-sectional views of a portion of the mold usedfor manufacturing the cap shown in the previous figures, showing thedifferent phases and manufacturing steps; and

FIG. 15 is a partial view of the mold shown in FIGS. 8 to 15, which hasbeen enlarged to facilitate identification of the most relevantstructural elements of said mold.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

The obturation cap 1 according to the preferred embodiment of theinvention as shown in the accompanying drawings is intended to be usedfor closing the neck of a water container devised for insertion in awater dispenser of the type disclosed in U.S. Pat. No. 5,222,530mentioned hereinabove.

This cap comprises a round-shaped lid 3, which is provided with acentral opening 5 which is also round-shaped.

An annular skirt 7 extends in a given direction all around the externalperiphery of the lid 3. This skirt 7 is provided with a central axis Aand is devised and sized to be connected to the neck of the container.The way this connection can be made is quite standard and needs not bedescribed in greater details.

In fact, the only information of interest is that, as is of commonpractice, the skirt is advantageously provided with a pulling tab 9associated to a frangible line made in the internal surface of the skirtto allow tearing of it and thus to facilitate removal of the cap fromthe neck of the container once the same is empty.

In addition, the internal surface of the lid and the internal surface ofthe skirt may be provided with rims 13 and 15. The rim 13 positioned onthe internal surface of the cap is coaxial to the opening 5 and isintended to be used to provide homogeneous filling of the mold cavityused for the manufacture of the cap during the injection phase, as willbe explained hereinafter. The rim(s) 15 provided on the internal surfaceof the skirt is (are) intended to improve water tightness and airtightness of the cap and thus to improve the hygienic properties of thecontainer.

To guarantee this tightness, an annular sealing joint 16 may be used ata suitable location, preferably at an internal junction between the lidand the skirt, as is shown in FIG. 1. This joint 16 is advantageouslymade of food approved resin and manufactured by injection, in order toprovide organoleptic properties protection and guarantee water puritywithin the container.

The external surface of the cap may also be provided with a central zoneforming a recess of about 0.5 mm to allow positioning of an irremovableseal 14 (see FIG. 1) whose purpose is:

-   -   to ensure protection against introduction of foreign elements        within the sleeve via the central opening 5, especially during        storing and transportation of the containers;    -   to provide a first level tamper-proof guarantee (the second        level is when the frangible connection of the plug is torn away,        as will be explained hereinafter); and    -   to allow easily readable identification by the consumer, of the        water source that is used and of the identity of the company        which has manufactured the container or filled it up.

Preferably, the seal 14 is welded instead of being glued, in order toavoid use of a glue that could be not alimentary, and also to excludethe risk of undesired sticking on the container after removal of theseal, thereby facilitating the task of the bottling industry whilereducing the cleaning cost when returnable containers are sent back tothe bottler.

The cap 1 also comprises a sleeve 17 in the form of an annular bodyextending all around the central opening 5 of the lid in the samedirection as the skirt 7 and coaxially with it. In practice, the centralopening 5 and the sleeve 17 surrounding the same are both sized toreceive and guide the feed tube of the liquid dispenser on which thecontainer closed by the cap is intended to be used (see FIGS. 4 to 7).

A plug 19 having an upper and 21 that is fully closed, is fixed in adetachable manner by means of a frangible connection 23 to the free edge25 of the sleeve 17. The plug which acts as an “obturator”, is coaxialto the sleeve 17 and devised to be separated from the same when thecontainer closed by the cap is intended onto the feed tube of the liquiddispenser (see FIG. 6).

As shown, the plug 19 is provided with internal gripping means 27 thatpreferably consists of a holding clip projecting radially within theplug in order to engage an annular slot provided near the upper end ofthe feed tube, as is shown in FIGS. 4 and 7.

The plug 19 is also provided with wings 20 intended to provide a propercentering of the same onto the upper end of the fed tube in use.

The plug 19 is further provided with external sealing means 29 to closethe sleeve 17 when the container is removed from the dispenser and theplug is moved to the back to the sleeve and force within the same by thefeed tube. These external sealing means 29 preferably consist of anexternal annular rim adjacent to the upper closed end 21 of the plug 19,which acts as a stop during extraction of the container (see FIG. 7)while coming into contact onto the free edge 25 of the sleeve.

The way the obturation cap 1 as previously disclosed works is similar towhat is disclosed in the prior art references mentioned hereinabove. Inthis connection, one may refer to FIGS. 5 to 7 which illustrate theoperation of the cap when a container closed by the same is insertedinto a liquid dispenser. FIG. 5 illustrates the cap during the insertionstep. FIG. 6 illustrates the cap once the container has been inserted.FIG. 7 illustrates the way the plug is forced into the sleeve to closethe cap in a tight manner when the container is removed from thedispenser.

As previously mentioned, a first characteristic of the invention, thatdistinguishes it over the prior art, is that the frangible connection 23between the sleeve 17 and the plug 19 is located in an angularlyoriented inlet zone made in the free edge 25 of the sleeve for, on theone hand, facilitating tearing of the frangible connection duringinsertion of the cap onto the feed tube of the liquid dispenser and, onthe other hand, facilitating engagement of the plug within the sleeveduring extraction of the feed tube.

More precisely, as is shown in FIGS. 2 and 4, the frangible connection23 is located in an inlet zone having a short portion 31 located abovethe frangible connection, with an inwardly oriented inclination angleranging from 20 to 60°, and preferably equal to about 45°, and a longerportion 33 located below the frangible connection, with an inwardlyoriented inclination angle ranging from 5 to 20°, and preferably equalto about 5°. It is worth noting that these angles could slightly vary,the only real requirement being that the inclination angle of theportion above the portion 31 of the zone 31 above the frangibleconnection be larger than the other so as to facilitate insertion of theplug within the sleeve during extraction from the feed tube.

To facilitate this engagement of the plug within the sleeve, the loweredge 35 of the plug 23 below the frangible connection where radiallyextend the annular rim 27 acting as internal gripping means, can also beinclined internally (see FIG. 2).

A second important characteristic of the invention is that the sleeve 17is molded with one or more sealing tongues 37 located on its innersurface.

The advantage of these sealing tongues 37 is that, while providingtightness of the sleeve during installation and removal of the plug toand from the sleeve, they also facilitate their assembly by ensuringprealignment of the plug within the sleeve.

The difference in diameter produced by the angulations of the sealingtongues 37 as shown in the drawings also has the advantage of ensuringprealignment of the plug within the sleeve during extraction of thecontainer closed by the cap, as is shown in FIG. 7.

A further advantage of these tongues is that at least one of them,preferably the one which is the closest to the free edge of the sleeve17, may act as a clip for holding the caps in order to provide externaltightness when the container is removed. The external peripheral part ofthe plug 19 may also be provided with an external tongue 26 cooperatingwith the “upper” tongue 37 to retain the plug when the container isreinserted within the liquid dispenser.

Last of all, as mentioned hereinabove, a third important characteristicof the invention is that the whole cap 1 previously disclosed, includingits lid 3, its skirt 7, its sleeve 17 and its plug 19 and all the otherelements that are parts of them, such as the rims 13, the sealingtongues 37, the sealing rings 15 and others, is molded in one singlepiece, without having to proceed to welding, glueing or other adjunctionof additional components or removable pieces as it is done in the priorart.

The fact that the cap is molded in one single piece, is important sincesuch permits to avoid contamination that may occur when the cap is madeof two or more pieces that must be stocked and handled before beingassembled.

The molding in one piece is also important inasmuch as it permits togive to the cap any desired color, which is impossible when the cap ismade of several pieces of plastic material that must be assembled bywelding or any other means.

Accordingly, the cap 1 according to the invention as disclosedhereinabove is very interesting inasmuch as it is made of one singlepiece of very “performant” structure.

Like the other caps of the same type disclosed in the closest prior artreferences, the fact that the plug 19 tearable at the end of the sleeve17 is insertable within the same sleeve, has the advantage of allowingremoval of the container from the liquid dispenser even when thecontainer is not fully empty. Such a removal may be required forcleaning the dispenser or for any other maintenance necessity. Such hasalso the advantage of allowing return of the container to the bottlerwhile protecting it against polluting agents, which, as a result, makeeasier the selection of suitable cleaning detergents.

In addition to the above mentioned advantages, the cap according to theinvention has the advantage of having a cylindrical frangible connection23 of very efficient structure, located between the free edge of thesleeve 27 and the plug. Contrary to the cap disclosed in theinternational application WO 02/060808 A1, the cap according to theinvention also has the advantage of having at least one and preferablytwo sealing tongues 37 that provides better tightness, less stress andeffort to remove the container from the liquid dispenser, and astructural reinforcement that facilitates removal of the cap from themold by rigidly filing the internal portion of the sleeve.

Moreover, the cap according to the invention may receive an annularsealing joint 16 to improve its tightness, and a seal 14 whoseadvantages have already been explained hereinabove.

Accordingly, the cap according to the invention provides a high hygienicguarantee since it is made of one single piece from a plastic materialthat is acceptable for alimentation purpose, within manufacturing placescertified for this type of service. The cap according to the inventionalso permits, thanks to its plug, an obturation of the cap during eachremoval of the container. Such is particularly important when thecontainer is not fully empty, since this avoids any risk of splash andcontamination. When the container is empty, the same security closingpermits, during return to the bottler, to use standard cleaning beforereuse without having to carry out a particular sorting.

The cap 1 according to the invention can be manufactured by injectionwithin the mold whose structure and operation in several steps andphases, are shown in FIGS. 8 to 15.

FIG. 8 and the left hand side of FIG. 14 illustrates phase 1, part 1 .The mold is then closed. As is better shown in the rounded spot on FIG.14, the injection of the cap 1 is made in a cavity 61 located on anexternal periphery 63, via a hot injection nozzle located on one side ofthe cap and fed by a heated distributor 67. The injection is thereforemade laterally at a spot 69 (see FIG. 3) located in a rim 72 formed atthe connection between the lid and the skirt of the cap.

FIGS. 9 and 15 illustrate phase 1, part 2. In this specific position,the injection mold is in opening phase (see the arrow “A” on FIG. 15).The sleeve 17 of the cap 1 is then extracted from a tubular member 40 bya pushing made by an ejecting ring 41 coaxial to the tubular member 40.During this pushing, a central core 43 mounted within the tubular member40 and whose lower end is located within the lid of the cap, is movedtogether with the same. This very specific motion has the advantage ofnot damaging or deforming the frangible connection between the sleeveand the plug of the cap. It is worth noting that in the production mold,the tubular member 40 is advantageously provided with adjusting meansthat permit to adjust and optimize the thickness of the frangibleconnection.

FIG. 10 illustrates phase 1, part 3. This particular step corresponds tothe end of the opening of the injection mold. The central core is thenextracted from the lid and the sleeve of the cap 1. During thisextraction, the lid 17 is retained by its rim 29. In fact, as is shown(see FIG. 15), the rim is then held in between a socket 49 and a tubularmember 51 in order to avoid damaging the frangible connection 23.

It is worth mentioning that the motions of phase 1, part 2 and phase 1,part 3 are achieved either by means of mechanical hooks (cylindrical orothers) or by means of hydraulic or pneumatic jacks 71 of single ordouble effects (see FIG. 14).

FIG. 11 illustrates phase 2, part 1, wherein the mold cap is extractedfrom the molding cavity (mobile part of the mold). This extraction ismade by a pushing made either by an ejecting machine and a two-timesejection system, or by means of single or double effect hydraulic jacks.This pushing causes a displacement of the core 47, in the middle ofwhich is mounted the socket 49, the tubular member 51 and the centralmember 52 (see FIG. 15). It is worth noting that the socket 49 and thecentral member 52 move simultaneously with the core 47. However, thetubular member 51 remains in position and thus liberates the rim 29 ofthe cap that was, so far, held between the pieces 49 and 51.

FIG. 1 2 illustrates phase 2, part 2. During this phase, the cap isextracted from the core 47. Such an extraction is made by means of apushing made either by the ejecting machine or the ejecting meansmounted within the same, or by hydraulic or pneumatic jacks with singleof double effect, which move the socket 49 and the central member 52.Simultaneously to this pushing, compressed air is injected within themold in order to uncompress the cavity and avoid deformation of themolded cap.

FIG. 13 illustrates phase 2, part 3. This phase comprises a finalextraction of the cap. This ejection is made by pushing the centralmember 52 within the socket 49 by means of pneumatic or hydraulic jackswith single of double effect, as mentioned hereinabove. Such ensuresextraction of the whole cap, including our course, its sleeve and block.This final extraction can be completed by a further injection ofcompressed air, it was already carried out in phase 2, part 2.

FIG. 14 illustrates phase 3, parts 1 and 2. During part 1 of this phase,the jacks having executed phase 2, part 3 are also moved back inoriginal position. Thus, the ejecting jacks are also moved back in theiroriginal molding position. During part 2, the two parts of the press areclosed and put back in position for a new injection. The molding cycleis then completed.

It is worth noting that contrary to the previous figures, FIG. 14illustrates a mold provided with two cavities instead of one. This hasbeen done for illustrative purpose, in order to show that, in use, thenumber of cavities may vary depending on the need and capacity of themold that is being used.

The method according to the invention as it has been detailedhereinabove may therefore be summarized as follows.

In a first step (phase 1, part 1), a plastic material is injected into amolding cavity in the form of the cap to be molded by means of aninjector 65 located laterally with respect to said cavity, the injectionbeing carried out laterally at a point 69 located onto the rim 71 formedby the lid and the annular skirts at their junction.

The molding cavity mentioned above is located in a mold comprising afirst part called “fixed part”, which is provided with a plurality ofaxially movable elements including:

-   -   a tubular member 40 having an external periphery acting as an        internal molding support for the annular sleeve 17 of the cap;    -   an ejecting ring 41 coaxially mounted externally around the        tubular member 40, and    -   a central core 43 coaxially mounted inside the tubular member 40        and having a lower end acting as an internal molding support for        the lid 19.

The mold also comprises a second part hereinafter called “moving part”,which is provided with a plurality of other axially movable elementsincluding:

-   -   another core 47 having an external upper periphery acting as an        internal molding support for the skirt 7 of the cap;    -   a socket 49 coaxially mounted inside the other core 47, the        socket having an upper edge and an upper internal periphery        acting as an external molding support for the sleeve 17 and the        plug 19 of the cap and for one part of the external sealing        means (viz. the annular rim 29) of the plug;    -   another tubular member 51 coaxially mounted inside the socket        49, said other tubular member having an upper edge acting as a        molding support for another part of the external sealing means        29 of the plug; and    -   a central member 52 coaxially mounted inside the other tubular        member 51, this central member having an upper surface acting as        an external molding support for the lid.

The mold further comprises actuating means (71 and others not shown) forseparating the fixed and movable parts of the mold and for pushing andpulling the above mentioned movable elements of the fixed and movableparts.

Of course, during this first step of injection, the fixed and movableparts of the mold are in adjacent position for completing and closingthe molding cavity.

In a second step (phase 1, part 2), separation of the fixed part and themoving part of the mold is started while holding the central member 40in original position. Such allows removal of the internal support of thesleeve while allowing the central core 43 to remain within the plug 19and move therewith.

In a third step (phase 1, part 3), separation of the fixed part and themoving part of the mold is continued in order to obtain extraction ofthe central core 43 from the plug 19 and the sleeve 17, the cap beingthen held within the moving part of the mold by means of its externalsealing means (viz. its rim 29).

In a fourth step (phase 2, part 1), the other core 47 is actuatedsimultaneously with the socket 49 and the other tubular member 1 toextract the cap from the moving part of the mold, such an extractionbeing carried out while maintaining the other tubular member 51 inoriginal position so as to liberate the external sealing means (viz. therim 29) of the plug from the moving part of the mold.

In a fifth step (phase 2, part 2), the socket 49 and the central member52 are actuated for extracting the cap from the other core 47, saidextraction liberating the skirt 7 of the cap.

In a sixth step (phase 2, part 3), the central member 52 is actuated soas to move it within the socket 49 in order to extract the whole cap.

Last of all, in a seventh and last step, all the movable elements andparts are brought back to their original position to start manufacturinganother cap.

The description hereinabove of every phase of operation of the mold formanufacturing the cap by injection in one single piece will allow anyone skilled in the art to understand how the inventors have solved theproblems mentioned in the prior art, which problems are associatedeither to manufacturing difficulties resulting in high cost or, moredrastically, to the impossibility of carrying out such an injection inone step (see again U.S. Pat. No. 5,392,939 mentioned hereinabove).

The originality of the mold disclosed hereinabove, and of its operationessentially lies in that, since the injection is made laterally on anexternal radius of the lid of the cap, a motion of the second centralcore on the fixed part of the mold then becomes possible. In addition,the combination of a double motion of the mold permits to preventdeterioration and deformation of the cap, by overcoming blocking due tocounter-stripping.

In other words, a double motion of ejection becomes possible due to thefact that the injection is made in the cavity 61 located on an externalperiphery 63 (see phase 1, part 1 as shown in FIG. 14). In addition, theuse of a tubular member 40 that is adjustable permits to optimize thethickness of the cylindrical frangible connection 23.

In practice, it should noticed that the use of an injection nozzlelaterally positioned onto the external periphery of the cap, makes itnecessary to provide a rim 13 onto the lid 3 in order to ensure properequilibrium of the central feed during injection. In the connection zonebetween the upper part of the cap and the skirt, a spot is provided foran injected sealing joint 16 as was mentioned hereinabove. This sealingjoint is a guarantee of tightness, taste and quality of the content ofthe container.

Of course, numerous other modifications could be made to the obturationcap disclosed hereinabove and shown in the drawings as well as to itsmethod of manufacture, without departing from the scope of the presentinvention as disclosed hereinabove.

1. In an obturation cap for a liquid container intended to be used inupside down position in a liquid dispenser provided with a feedingsystem including a feed tube, said cap comprising a lid provided with acentral opening; an annular skirt extending in a given direction allaround an external periphery of the lid, said skirt being provided witha central axis and being devised and sized to be connected to the neckof the container; said skirt being provided with internal surfaceprovided with at least one rim positioned to improve water tightness ofthe cap once said cap has been mounted onto the neck of the bottle; anannular sleeve extending all around the central opening of the lid inthe same direction as the skirt and coaxially therewith, the centralopening and the sleeve surrounding the same being both sized to receiveand guide the feed tube of the liquid dispenser used with the containerclosed by the cap; and a plug fixed in a detachable manner by means of afrangible connection to a free edge of the sleeve opposite to thecentral opening, said plug being coaxial to the sleeve and devised to beseparated from the same when the container closed by the cap is insertedinto the liquid dispenser, the frangible connection between the sleeveand the plug being located in an angularly oriented inlet zone made inthe free edge of the sleeve for, on one hand, facilitating tearing ofthe frangible connection during insertion of the cap onto the feed tubeof the liquid dispenser and, on the other hand, facilitating engagementof the plug within the sleeve during extraction from the feed tube, theplug then acting as an obturator, said plug being also provided withinternal gripping means for fixing it temporarily to an upper end of thefeed tube during water flow, and with external sealing means for closingthe sleeve when the container is removed from the liquid dispenser, theplug being then pulled back to the sleeve and forced into the same bythe feed tube while the same is extracted from the sleeve, wherein saidsleeve further comprises a plurality of sealing tongues provided on aninner surface thereof, wherein the inner diameter of the sealing tonguesdecreases in a direction toward the lid, and increases in an oppositedirection toward the free edge of the sleeve, for aligning the plugwithin the sleeve during extraction from the feed tube.
 2. The capaccording to claim 1, wherein the angularly oriented inlet zonecomprises a portion above the frangible connection being inwardlyoriented and a portion below the frangible connection being inwardlyoriented, the portion above the frangible connection having an inwardlyoriented inclination angle ranging from 20° to 60°.
 3. The cap accordingto claim 2, wherein the portion above the frangible connection has aninwardly oriented inclination angle of about 45°.
 4. The cap accordingto claim 1, wherein the angularly oriented inlet zone comprises aportion above the frangible connection being inwardly oriented and aportion below the frangible connection being inwardly oriented, theportion below the frangible connection having an inwardly orientedinclination angle ranging from 5° to 45°.
 5. The cap according to claim4, wherein the portion below the frangible connection has an inwardlyoriented inclination angle of about 45°.
 6. The cap according to claim1, wherein said plurality of sealing tongues comprises a first sealingtongue adjacent the free edge of the sleeve, and a second sealing tongueprovided between the first sealing tongue and the central opening in thelid.
 7. The cap according to claim 1, wherein the plug comprises anexternal tongue provided on an exterior surface thereof between theexternal sealing means and the internal gripping means, said externaltongue for clipping on the first sealing tongue of the sleeve forretaining the plug when the feed tube is re-inserted in the sleeve. 8.The cap according to claim 1, wherein the plug comprises at least onewing provided on an inner side of a closed end of the plug for centeringthe feed tube when the feed tube is inserted in the plug.
 9. The capaccording to claim 1, wherein said lid, said skirt, said sleeve and saidplug of the cap are made in one piece without welding or adjunction ofan additional component or a removable piece.
 10. The cap according toclaim 1, further comprising a water-tight annular sealing jointpositioned between the rim and the annular sleeve, wherein the annularsealing joint is positioned at an internal junction between the lid andthe skirt.
 11. The cap according to claim 1, wherein the lid and theannular skirt together have a junction forming a rim allowing injectionof plastic material from an external radius of the lid.